The invention pertains to a hard composite that is made via sintering techniques. More specifically, the invention pertains to a hard composite that is made via sintering techniques that are able to control the extent and depth of cobalt enrichment in the region of the surface of the hard composite.
In hard composites like cemented tungsten carbides, the binder (e.g., cobalt) content has an influence on the properties of the composite. For example, an increase in cobalt content typically leads to an increase in toughness of the composite. Heretofore, there has been a desire to be able to have a binder-enriched region near the surface of a hard composite. For example, United States Reissue Pat. No. 34,180, to Nemeth et al., assigned to the assignee of the present patent application, discloses a method that produces a hard composite with binder enrichment in the surface region, as well as discloses such a product.
Typical applications that would find hard composites that have surface binder enrichment to be desirable would be wear applications, mining applications, construction applications, and metalcutting applications. Wear parts like wire drawing dies would find a hard component with such a microstructure to be advantageous. In the mining applications, mining tools like roof bits, open face style tools, and conical style tools would find a use for a hard insert with a microstructure presenting binder enrichment in the surface region. In the construction applications, rotatable construction tools would find a hard insert with a microstructure presenting binder enrichment in the surface region to be advantageous. In metalcutting applications, a cutting tool that has a microstructure with binder-enrichment in the surface region would be advantageous.